Yol. 52.] ASSOCIATED BEDS, IN N. DEVON AND W. SOMERSET. 271 



graptolites, he thought that the first was an imbricated shell, like an 

 Atrypa, perhaps A. aspera, but that it certainly did not show the 

 cross-ribbed surface from which C. interrupta took its name. The 

 second was founded on distorted specimens of Spirifera disjuncta ; 

 and the so-called graptolites were lines of an asbestiform mineral 

 following broken vein-like cavities, which had perhaps in some 

 cases been occupied by encrinite-arms and stems, the joints of which, 

 together with regular step-like displacements during the movements 

 that modified the structure of the rock, produced the scalariform 

 appearance of graptolites. 



The Author had added greatly to our knowledge of the Devonian 

 rocks by his discovery of fossils in the Morte Series, but the speaker 

 thought that the rocks and fossils suggested a comparison with the 

 Tintagel Beds rather than with the Silurian. 



The Rev. G. F. Whidjborne had had the privilege of following 

 the Author's work in the field and collecting fossils with him, and he 

 was convinced that the Author had not only found an abundant fauna 

 in the ' unfossiliferous ' Morte Slates, but had discovered the true 

 bedding-planes, and thereby proved the thickness of the deposits in 

 North Devon to be much less than had been supposed. He had very 

 carefully examined the fossils on the table, and was convinced that 

 they did not present a Devonian facies. He had been unable to 

 reconcile them with any Devonian fauna that he knew. Nor could 

 he agree with Prof. Hughes that the large specimen of StricJclandinia 

 lirata could by any possibility be a distorted Spirifer Verneuili. 

 It differs from that form both in shape and minute ornament. 

 The fragment of ' Gardiola interrupta ? ' also seemed to be more 

 like that fossil than anything else, though it was difficult 

 to determine in its fragmentary condition. It certainly was not 

 Atrypa aspera. 



Mr. Mark said that the dip of the Ilfracombe Beds from the Morte 

 Slates below the supposed thrust-plane was not evidence of the 

 existence of a thrust-plane. But the serious evidence was that of 

 the fossils. He maintained that none of the fossils exhibited were 

 definitely proved to be Silurian. He could not see any indications 

 of graptolitic structure in the specimens on the table. The greatest 

 stress had been laid on the supposed StricJclandinia lirata. He 

 wished that the gentleman who had identified that specimen had been 

 present to say definitely that it was StricJclandinia. Considering 

 the number of forms closely related to Silurian forms which had 

 been found in American Devonian rocks (for example, Pentamerus 

 pseudogaleatus), and the fact that in the richly fossiliferous deposits 

 of Bohemia, Barrande's stages F, Gr, H, now shown by Kayser to be 

 Devonian, were originally described as Silurian, he did not think 

 that the distorted fossils displayed on the table could be taken as 

 evidence for upsetting the received classification of the North 

 Devon rocks. The Author was to be congratulated on the discovery 

 of fossils in these supposed barren rocks, but the speaker, though 

 having no objection to the reference of the Morte Slates to the 

 Silurian, hoped that more evidence would be forthcoming in the 



